MXPA98009142A - Composition and method for inhibiting the growth of microorganisms, which includes sodium hypobromite stabilized and isotiazolo - Google Patents

Abstract

The present invention relates to a synergistic composition and to a method for inhibiting microbiological growth, which comprises a combination of stabilized sodium hypobromite, with a mixture of 5-chloro-2-methyl-4-isothiazolin-3-one and -methyl-4-isothiazolin-3-o

Description

COMPOSITION AND METHOD TO INHIBIT GROWTH OF MICROORGANISMS, WHICH INCLUDES HYPOBROMIT OF SODIUM STABILIZED AND ISOT IAZOLONAS FIELD OF THE INVENTION The invention consists of a composition for controlling microbiological growth, which comprises a combination of stabilized sodium hypochloride with a mixture of 5-chlor or-2-methyl 1-4-isothiazine 3 -one and 2 -me ti 1- 4 -is otiazol in-3 -one. The invention also consists of a method for controlling microbiological growth, which comprises a combination of sodium hypobromite, stabilized with a mixture of 5-chloro-2-methyl-4-isot-iazo lin-3 -one and 2-methyl. ti 1 - 4 -is ot iazol in-3 -one.

BACKGROUND OF THE INVENTION The proliferation of microorganisms and the resulting formation of lama is a problem REF .: 28796 that commonly occurs in aqueous systems. The problematic lama that produces microbes can include: bacteria, fungi, and algae. Lama deposits are typically presented in many industrial aqueous systems which include water cooling systems, pulp and paper mill systems, oil installations, liquid clay pastes and pigments, aquatic recreation systems, air washing systems, sources of decoration past eur i zadores of industrial processes of foods and of beverages, systems of fresh water, systems scrubbers of gases, systems of latex, industrial lubricants, fluids to realize cuts, etcetera. Biocides and antimicrobials are used to control or eliminate microbial growth in a number of different aqueous media. If left untreated, microbes and biological microbial films (lamas) can cause deterioration of cooling tower structures, loss of heat exchange efficiency in a cooling system, aesthetic defects in decoration sources, the promotion and acceleration of corrosion of metal surfaces, increased periods of paralysis, or ruptures of paper sheets in pulp and paper systems. Bacterial lamas can also be objected as they are related to the lack of cleanliness and sanitation of the water systems of breweries, dairies, and other industrial processes of food and beverages. The proliferation of microbial contamination in lubricants and fluids used to make cuts is a common problem due to the high temperatures and unhealthy conditions found in many metalworking plants. As a consequence of the harmful effects of uncontrolled microbial growth and contamination, in many industrial processes, different antimicrobial products have been developed to help eliminate microbial growth. Often, an antimicrobial agent (biocide) is sufficient to control microbial growth in aqueous media. Biocides can act in combination, ie synergistically, to produce a better antimicrobial performance, which is contrary to the effectiveness obtained when each biocide is used separately. Biocides can act on the target microbe in a number of different ways to cause fatigue or cell death. The mechanisms through which biocides exert antimicrobial activity depend on factors that include the chemical properties of the antimicrobial agent, and the biochemical and physical characteristics of the target microbe. Some biocides attack the cell membrane or the cell wall. Others attack or target certain critical enzymes or the cellular metabolic apparatus, which leads to cell death or the breakdown of cell multiplication. The combination of two biocides can produce an improved efficacy that goes beyond the cumulative or additive effect of the two biocides. This probably reflects a synergistic antimicrobial effect on certain essential component (s) of the cell, for its survival and sustained growth. A combination of two biocides that are synergistic allows the addition of smaller amounts of the individual biocides to achieve the desired level of microbial control. This has both environmental and economic impacts, which are advantageous. It allows the reduced discharge of potential environmental pollutants and a more effective control program in relation to the cost, for these diverse industrial systems. For this invention, the methyl chloroform / iso-ti-olino dicacid is a broad spectrum antimicrobial agent which is widely used in industrial systems to control algae, bacteria, and fungi. Commercial preparations of the compound, for use as a biocide for cooling towers (KATHONmr WT; an agent for microbial control available at Rohm and Hass Company, Philadelphia, Pennsylvania) are water-based formulations of stabilizers and inorganic active ingredients. The active ingredients, 5-chloro-2-methyl, 1-4-iso-t-1-in-3 -one and 2-met-il-4-iso-thiazolin-3-one, are present in a ratio of approximately 3: 1. Isothiazolones are effective against many microorganisms. The microbicidal activity of isothiazolones is probably due to their elective nature and their interaction with certain key enzymes such as cellular dehydrogenases as well as the pronounced effect they have on cellular respiration. In a previous investigation it was shown that isothiazolones can be used to demonstrate a significant disinfection of a bacterial biological film, although it is not a good agent to remove the adherent biological film. Conversely, the stabilized sodium hypohydrate can act as a penetrating agent and break the adhered biomass. Therefore, the persistence of isothiazolones, coupled with the reactivity and removal properties of the biological film, stabilized sodium hypobromite, produces an antimicrobial composition with superior performance, compared to the results obtained when using a single biocide independently. Also, the combination of these two biocides clearly exerts an improved (synergistic) antimicrobial effect on the planktonic microorganisms, as indicated in the data shown herein. The exact mechanism for this observed synergy remains unknown. It is an object of the present invention to provide novel antimicrobial compositions that offer improved effectiveness for controlling or inhibiting the growth of microorganisms in aqueous systems. Another objective of this invention is to provide an improved method for controlling microorganisms in aqueous systems. An advantage of the present invention is that the biocidal compositions allow a reduction in the required amount of biocide to achieve an acceptable microbiological control. Important applications of the antimicrobial compositions of the present invention include, but are not limited to, the inhibition of growth of bacteria and fungi in aqueous media. The composition of the present invention possesses unexpected synergistic activity against microorganisms including bacteria and fungi. Stabilized sodium hypobromite is less volatile and more stable than other halogenated molecules such as sodium hypochlorite and sodium hypobromite. Also, much higher levels of available halogen are achieved for microbial disinfection, using stabilized sodium hypobromite, instead of other halogenated antimicrobial agents. Bromate formation is significantly reduced with the use of stabilized sodium hypobromite (1997, Dallmier, A. W. and W. F. McCoy, PCT Int. Appl., WO 9734827). The US EPA identified some health-related aspects that are relevant to the formation of bromates (1995, A and, G. et al Water Supply, 13 (1): 157). Carcinogenesis in animals has been associated with low levels of bromatos in drinking water (J. K. and G. O'Neill, Water Supply, 13 (1): 29). In addition, stabilized sodium hypobromite produced a reduced generation of organic halogens that can be adsorbed (AOX) in laboratory and process water studies. Stabilized sodium hypobromite produces a significant reduction in viable microbial contaminants at concentrations between 1.0 and 2.0 ppm total residual oxidant (such as chlorine). The mixture of isothiazolones (1.5% active ingredients) is typically used in concentrations of 100 to 200 ppm as a product to obtain similar reductions in microbial populations. This invention provides superior microbiological control by combining stabilized sodium hypobromite, with a mixture of 5-chloro-2-methi 1-4-isot-iazo-lin-3-one and 2-methyl-4-i-t-tiazol-3-one. The combination of two antimicrobial agents allows significantly lesser use of any of the antimicrobial agents, compared to the amount needed for each individual antimicrobial agent, to achieve the same biocidal performance. As is well known in the art, the substances exhibit synergistic antimicrobial properties when combined with other biocides. The synergistic mixtures of 5-chloro-2-met i 1-4-isothiazolin-3 -one and 2-met-il-4-i so-thiazol-3-one, with glutaraldehyde, are described in the U.S. Pat. No. 4,539,071; with dodecylguanidine hydrochloride are described in U.S. Patent No. 4,661,503; and with 2- (thiocyanomet il thio-) benzo thiazole are described in U.S. Patent No. 4,595,691. The Pocius reference (U.S. Patent No. 4,295,932) describes a synergistic composition of isothiazolones, either with chlorine or with chlorine dioxide. Microbicidal compositions containing halogen-releasing compounds are described in WO 96/14092. However, the synergistic biocidal composition, described herein, was not described or suggested by the references mentioned above.

BRIEF DESCRIPTION OF THE INVENTION The present invention relates to a biocidal, synergistic mixture of stabilized sodium hypobromite, with a mixture of 5-chloro-2-me t -yl-4-isotriazole 3-one and 2-met i 1-4 -isothiazolin-3-one.

DETAILED DESCRIPTION OF THE PREFERRED MODALITIES The present invention provides, under one embodiment, for inhibiting the growth of microorganisms in industrial fluids, a composition comprising a combination of stabilized sodium hypobromite and a mixture of 5-chloro-2-methyl-1-4-y soo-azol. in 3 -one and 2-me ti 1- 4-is otia zo 1 in 3 -one. This composition can be used in a method to control microbiological growth. For the practice of this invention, microbiological growth can be selected from the group consisting of bacteria, fungi, algae, and combinations thereof. Stabilized sodium hypobromite can be sodium hypobromite stabilized with sodium sulphate. The sodium hypobromite can be stabilized with an alkali metal sulphamate, such as sodium sulphamate, in addition, the sodium hypobromite can also be stabilized with an acid amide derivative selected from the group consisting of: carbonic acids, hydrogen cyanide , carboxylic acids, amino acids, sulfuric acids, phosphoric acids, and boric acids. The method can be applied to industrial fluids selected from the group consisting of recirculating cooling waters; process waters for food, beverages and industrial, paper mill systems; pas teur i z adores of breweries; systems for air washing; fluids and sludge for drilling oil fields, heat transfer systems, and fountains for decoration, among others. The amount of stabilized sodium hypobromite can vary from about 0.05 ppm to about 10 ppm, of total residual oxidant, and the amount of the mixture of 5-chloro-2-me t yl- 4 -is ot ia zol in-3- ona and 2-methyl-1,4-siathia-3-one varies from about 0.05 ppm to about 6.0 ppm of active ingredient. The composition and method can be used to control bacteria in recirculating cooling water, wherein the weight ratio of the mixtures in stabilized sodium hypobromite ratio is from about 1.0: 10.0 to about 10.0: 1.0; for controlling fungi in recirculating cooling water, wherein the weight ratio of the mixtures to the stabilized sodium hypobromite is from about 1.0: 10.0 to about 10.0: 1.0; to control algae in recirculating cooling water, wherein the weight ratio of the mixtures, with respect to the stabilized sodium hypobromite, is from about 1.0: 10.0 to about 10.0: 1.0; for controlling bacteria in paper mill systems, wherein the weight ratio of the mixtures, with respect to the stabilized sodium hypobromite, is from about 1:10 to about 10: 1. When the method is used to control microbial growth, the pH of the recirculating cooling water can be controlled to be within a range of about 2.5 to about 11.0. In more preferred ways, the pH can be controlled within the range of about 6.0 to about 10. The composition includes a sufficient amount of any of the biocides, to obtain an acceptable microbiological control in an aqueous system (an effective amount of antimicrobial agent). . A typical concentration for industrial use of stabilized sodium hypobromite could be in the range from about 0.05 to about 10 ppm total residual oxidant (such as chlorine) and a typical use concentration of the isothiazolone mixture could be found in the range that goes from approximately 0.05 to 6.0 ppm, as an active ingredient (active ingredient refers to the amount of isothiazolones in the aqueous solution). The term residual oxidant, as used herein, is defined as hypohalite or hypohalide acid, including the guanic combinations of those two compounds, with ammonia or with organic compounds containing nitrogen. Important applications of the synergistic antimicrobial compositions of the present invention include, but are not limited to, the inhibition of the growth of bacteria, fungi, and algae, in cooling water systems, freshwater systems, water treatment systems, gases, pulp and paper mill systems, control of microbial contamination and deposits in fluids and sludges for drilling oil fields, oil recovery processes, control of the growth of bacteria and fungi in liquid clay and pigment pastes, systems of latex, air washing systems, and pass t ets for industrial processes, food and beverages. The mixture of isothiazolones used for the practice of this invention is commercially available as an aqueous solution with 1.5% of active ingredients and includes a mixture of 5-chloro-2-methyl-4-yl iso-thiazole-3 -one and 2-me ti 1- 4 -iso tiazolin-3 -one. As used herein, the term "stabilized sodium hypobromite" indicates NaOBr stabilized with sodium sulfamate. However, NaOBr can be stabilized with other stabilizers including the acid amide derivatives of: carbonic acids, hydrogen cyanide, carboxylic acids, amino acids, sulfuric acids, phosphoric acids, and boric acids. In addition, the stabilizers can be selected from the group of compounds having an N-H or NH2 group, adjacent to an electron-withdrawing functional group such as C = 0, S = 0, P = 0, or B = 0. Stabilization of NaOBr is desirable to prevent molecular disproportionation to halolates and halides during storage. As a result of stabilization, these biocides can be stored more safely since less bromate is generated, fewer organic molecules containing halogens are formed, and volatility is reduced. An aqueous, stabilized solution of alkali metal or alkaline earth metal hypobromite can be prepared in the following manner: a. Mix an aqueous solution of alkali metal or alkaline earth metal hypochlorite having from about 5 percent to about 70 percent available halogen such as chlorine, with a source of water-soluble bromide ions; b. Allowing the source of bromide ions and the alkali metal or alkaline earth metal hypochlorite to react, to form an aqueous solution with a concentration of 0.5 to 70 weight percent, of alkaline or alkaline earth metal hypobromite, not stabilized; c. Add to the non-stabilized solution of alkali metal or alkaline earth metal hypobromite, an aqueous solution of an alkali metal sulphamate, in such an amount to provide a molar ratio of alkali metal sulfamate to alkaline or alkaline earth metal hypobromite, from about 0.5 to approximately 7; and d. Recover an aqueous solution, stabilized, hypobromite of alkaline or alkaline earth metal. The stabilized sodium hypobromite, used herein, is available from Nalco Chemical Company of Naperville, IL under the tradename of STABREX The synergistic composition of this invention can be added separately, to an industrial system, or it can be formulated as a simple mixture comprising its essential ingredients. It may be the case that stabilized sodium hypobromite acts synergistically when combined with other non-oxidizing biocides. It is expected that the detailed description given above will also apply to the composition and method for other non-oxidizing biocides. Examples of other non-oxidizing biocides are glutaraldehyde, 2,2-dibromo-3-ni tr i lopropionamide (DBNPA), alkyl dimethyl t-l-benzyl ammonium chloride (ADBAC), dimeyl chloride Idialqui lamonium , you me 1 enbi st ioci anat (MBT), 2-decylthioethane ina (DTEA), tetraquishydroxymethyl phosphonium sulfate (THPS), dithiocarbamate, cyanodi thioimidocarbonate, 2-me thi-5-ni t-roimidazole-1 -et anus 1, 2- (2-bromo-2-ni troeteni 1) furan (BNEF), beta-bromo-beta-nitroe st ir eno (BNS), beta-ni troe st irene (NS), be t a-ni t vini 1 fur anus (NVF), 2-bromo-2-bromomethyl-glutarium trile (BBMGN), bis (trichloromethyl) sulfone, S- (2-hydroxypropyl 1) thiomethansulfonate, t-tetrahydro-3,5-dimethyl-2H-1 , 3,5-hydrazine-2-thione, 2 - (t iocyanomet il thio) benzothiazole (TCTMB), 2-bromo-4 '-hydroxyacetophenone, 1,4-bis (bromoacetoxy) -2-butene, bi s (tributyl grade) oxide (TBTO), copper sulfate, 2- (tert-butyl-lamino) -4-chloro-6- (ethylamino) -s-triazine, dodecylguanidine acetate and dodecyl hydrochloride Iguanadine (DGH). The following examples are presented to describe the preferred embodiments and utilities of the invention and are not presented with the intention of limiting the invention unless otherwise stated in the claims appended thereto.

One example The efficiency of the invention was analyzed in the following manner. The plant was grown on an overnight basis, overnight, in L-broth, then washed and resuspended in sterile, sterile cooling water, consisting of 150 ppm of calcium, 75 ppm of magnesium, and 110 ppm of alkalinity, at a pH of about 8.0. For the test, 20 ml of sterile, synthetic sterile cooling water was added per test tube. Approximately 0.25 ml of the washed bacterial suspension and the indicated amount of biocide were added to the appropriate test tubes. After a contact time of 18 hours with the biocides, the cells were serially diluted and plated on tryptone glucose extract agar (Difco, Detroit, MI). Plates were incubated at 37 ° C for 24 hours, then labeled for viable counts. Viable bacterial counts are reported as colony forming units (CFU / l). The synergism is determined through an industrially accepted method such as that described by Kull, F.C., Eis an, P.C., Sylwes t ro icz, H.D. and Mayer, R.L. in Appl i e d My crobi ol or gy, 9: 538-541 (1961), using the equation for the calculation of a synergy index determined by: Qa + Qb_ = Synergy index (Is.) QA and QB where QA = concentration of compound A in parts per million (ppm) acting alone, which produces a final point; Qa = concentration of compound A in ppm, in the mixture, which produces a final point; QB = concentration of compound B in ppm acting alone, which produces a final point; Qb = concentration of compound B in ppm, in the mixture that produces a final point.

When the sum of Qa / QA and Qb / QB is greater than 1.0, an antagonism is indicated. When the sum is equal to 1.0, the additivity is indicated, and when the sum is less than 1.0, the synergy is demonstrated.

TAB LA I Biocide Amount of Count1 Classification Bacterial Biocide Index of (ppm) (CFU / mL) Synergy Synergy None None 16,000,000 A 0.25 10,800,000 A 0.50 4,300,000 A 0.75 400,000 A 1 .0 20,000 A 2.0 3,000 B 20 5,300,000 B 40 1, 100,000 B 80 530,000 B 160 90,000 A / B 0.25 / 20 120,000 A / B 0.25 / 40 120,000 A / B 0.25 / 80 40,000 A / B 0.25 / 160 5,000 A / B 0.50 / 20 33,000 A / B 0.50 / 40 3,000 0.75 Yes A / B 0.50 / 80 1, 400 0.75 Yes A / B 0.50 / 160 60 A / B 0.75 / 20 24,000 A / B 0.75 / 40 5,000 0.63 Yes A / B 0.75 / 80 3,200 0.88 Yes A / B 0.75 / 160 30 A = STABREX "11, stabilized sodium hypobromite, available from Nalco Chemical Company, Naperville, IL, Biocide measured as ppm of total residual oxidant, B = Mixture of 5-chloro-2-methyl-4-isothiazolin-3-one and 2-methyl-4-isothiazolin-3-one (1.5% active ingredients, available from Rohm and Haas Company, Philadelphia, PA) Biocide measured as ppm of the product 1 = measurement taken at 6 pm, at the initial time ( t == 0), bacterial count = 8,000,000 CFU / ml.

E jmplo Do s The procedure described in Example One was used to obtain the results of Table II. However, for this example, the test inoculum consisted of a mixed population of cooling water bacteria, obtained from a functioning cooling tower, from the Midwest region of the United States. Synergy was indicated.

TABLE I I Siocida Amount of Counting1 Classification Bacterial Biocide Index of (ppm) (CFU / L) Synergy Synergy None None 22,000,000 • A 0.5 16,000,000 A 0.75 8,100,000 A 1 .0 2,400,000 A 2.0 19,000 B 25 500,000 B 50 100,000 B 100 900,000 B 200 130,000 A / B 0.5 / 25 300,000 A / B 0.5 / 50 37,000 A / B 0.5 / 75 70,000 A / B 0.5 / 100 600 0.75 Yes A / B 0.75 / 25 5,000 0.51 Yes A / B 0.75 / 50 3,000 0.63 Yes A / B 0.75 / 75 300 0.76 Yes A / B 0.75 / 100 900 0.88 Yes A / B 1.0 / 25 1, 000 0.63 Yes A / B 1.0 / 50 100 0.75 Yes A / B 1 .0 / 75 < 100 0.88 Yes A / B 1.0 / 100 < 10 A = STABREX, stabilized sodium hypobromite, available in Nalco Chemical Company, Naperville, IL, Biocide measured as ppm of the total residual oxidant. B = Mixture of 5-chloro-2-methyl-4-isothiazolin-3-one and 2-methyl-4-isothiazolin-3-one (1.5% active ingredients, available from Rohm and Haas Company, Philadelphia, PA). Biocide measured as ppm of the product. 1 = measurement taken at 18 hours; at the initial time (t = 0), bacterial count = 11,000,000 CFU / l.

Ex empl o Three The procedure described in Example One was used to obtain the results of Table II. Sulfamic acid is not considered biocidal. Therefore, an endpoint could not be determined nor could a synergy index be calculated. These data indicate that there is no synergy between the sulfamic acid and the isothiazolone mixture.

TABLE III Product Quantity Counting1 Chemical (ppm) Bacterial (CFU / mL) None None 34,000,000 C 0.5 32,000,000 C 1 26,000,000 C 2 23,000,000 C 4 38,000,000 38,000,000 C 8 C 10 32,000,000 1,900,000 B 40 1,200,000 B 80 160,000 B 40,000 B 160 200 20,000 B 0.5 / 20 1,600,000 C / B 4,400,000 C / B 0.5 / 40 0.5 / 80 250,000 C / B 200,000 C / B 0.5 / 160 1.0 / 20 4,700,000 C / B 2,600,000 C / B 1.0 / 40 250,000 C / B 1.0 / 80 1.0 / 160 20,000 C / B 3,900,000 C / B 2.0 / 20 700,000 C / B 2.0 / 40 200,000 C / B 2.0 / 80 43,000 C / B 2.0 / 160 B = Mixture of 5-chloro-2-methyl-4-isothiazolin-3-one and 2-methyl-4-isothiazolin-3-one (1.5% active ingredients, available from Rohm and Haas Company, Philadelphia, PA). Biocide measured as ppm of the product. C = Sulfamic acid, available from PMC Specialty Group, Inc., Rocky River, Ohio. 1 = measurement taken at 16 o'clock; at the initial time (t = 0), bacterial count = 12,700,000 CFU / l.

Example Four The following procedure was used to obtain the results of Table IV. The test organism, the Ca di di gu il 1 e rm on di i (yeast) was grown overnight in L-broth at 30 ° C, then washed, and resuspended in synthetic cooling water, sterile (pH = 8.0) consisting of 150 ppm of calcium, 75 ppm of magnesium, and 110 ppm of alkalinity. To perform the assay, the yeast cells were exposed to the biocides for analysis and plated on acidified potato dextrose agar (Difco, Detroit, MI). Plates were incubated for two days at 30 ° C, and counts of viable colonies were recorded. All counts are expressed as viable yeast cells, recovered as CFU / ml. Synergy was indicated.

TABLE IV Biocide Quantity of Count1 Classification Bacterial Biocide index of (ppm) (CFU / mL) Synergy Synergy None None 700,000 A 0.25 190,000 A 0.5 900,000 A 1.0 100,000 A 2.0 80,000 B 5.0 20,000 B 10.0 40,000 B 20.0 1,100 B 40.0 100 B 50.0 100 A / B 0.25 / 5 30,000 A / B 0.25 / 10 20,000 A / B 0.25 / 20 100 0.63 If A / B 0.25 / 40 < 100 A / B 0.50 / 5 32,000 A / B 0.50 / 10 8,000 0.75 Yes A / B 0.50 / 20 200 0.75 Yes A / B 0.50 / 40 < 100 A STABREX, stabilized sodium hypobromite, available in Nalco Chemical Company, Naperville, IL. Biocide measured as ppm of the total residual oxidant. B = Mixture of 5-chloro-2-methyl-4-isothiazolin-3-one and 2-methyl-4-isothiazolin-3-one (1.5% active ingredients, available from Rohm and Haas Company, Philadelphia, PA). Biocide measured as ppm of the product. 1 = measurement taken at 5 o'clock; at the initial time (t = 0), bacterial count = 210,000 CFU / ml.

E jmplo Five The capacity of the agents used in the treatments was also analyzed using a mixed bacterial population, coming from a pulp and paper mill. A sample of pulp and paper white water was taken from a pulp and paper mill located in the Midwest of the United States. The analysis protocol described in Example One was used. The results are detailed in Table V. Synergy was indicated.

TABLE V Biocide Quantity of Count1 Classification Bacterial Biocide Indicated of (ppm) (CFU / mL) Synergy Synergy None None 10,000,000 A 2.5 1, 200,000 A 5.0 250,000 A 10.0 100,000 A 20.0 8,000 B 25.0 13,000 B 50.0 10,000 B 100.0 8,000 B 200.0 8,000 A / B 2.5 / 25 3,000 0.38 Yes A / B 2.5 / 50 8,000 0.63 Yes A / B 2.5 / 100 5,000 A / B 2.5 / 200 5,000 A / B 5.0 / 25 15,000 A / B 5.0 / 50 1, 000 0.75 Yes A / B 5.0 / 100 1, 000 A / B 5.0 / 200 9,000 A = STABREX ^, stabilized sodium hypobromite, available in Nalco Chemical Company, Naperville, IL. Biocide measured as ppm of the total residual oxidant. B = Mixture of 5-chloro-2-methyl-4-isothiazolin-3-one and 2-methyl-4-isothiazolin-3-one (1.5% active ingredients, available from Rohm and Haas Company, Philadelphia, PA). Biocide measured as ppm of the product. 1 = measurement taken at 7 pm; at the initial time (t = 0), bacterial count = 1,900,000 CFU / ml.

E xemplo Six The procedure described in Example One was used, to obtain the results of T la VI. Synergy was indicated. TABLE VI Biocide Quantity of Count1 Classification Bacterial Biocide index of (ppm) (CFU / mL) Synergy Synergy None None 50,000,000 D 0.5 18,000 D 1.0 1,300 D 2.0 < 100 D 4.0 < 10 D 6.0 < 10 B 25.0 3,500,000 • B 50.0 700,000. B 100.0 520,000 B 200.0 50,000 D / B 0.5 / 25 < 100 0.38 Yes D / B 0.5 / 50 < 1, 000 0.50 If D / B 0.5 / 100 < 100 0.75 Yes D / B 0.5 / 200 < 100 D / B 1.0 / 25 < 1, 000 D / B 1.0 / 50 < 100 0.75 Yes D / B 1.0 / 100 < 100 D / B 1.0 / 200 < 100 B = Mixture of 5-chloro-2-methyl-4-isothiazolin-3-one and 2-methyl-4-isothiazolin-3-one (1.5% active ingredients, available from Rohm and Haas Company, Philadelphia, PA). Biocide measured as ppm of the product. D = Hypobromous acid prepared from a solution of elemental bromine obtained from Aldrich Chemical Co. , Milwaukee, Wl. Biocide measured as ppm of the total residual oxidant. 1 = measurement taken at 5 o'clock; at the initial time (t = 0), aerobic bacterial count = 10,000,000 CFU / l.

Changes can be made in the composition, operation and arrangement of the method of the present invention described herein, without departing from the concept and scope thereof, as defined in the following claims.

Claims (23)

1. A composition for controlling microbiological growth, in industrial fluids, characterized in that it comprises a combination of stabilized sodium hypobromite, with a mixture of 5-chloro-2-methyl-1-4-y-iso-1-in-3 -one and 2 -me ti 1- 4 - isotiazolin 3 -one.

2. The composition according to the rei indication 1, characterized in that the microbiological growth is selected from the group consisting of bacteria, fungi, algae, and combinations thereof.

3. The composition according to claim 1, characterized in that the stabilized sodium hypobromite is sodium hypobromite stabilized with sodium sulfamate.

4. The composition according to the rei indication 3, characterized in that the sodium hypobromite is stabilized with an alkali metal sulphamate.

5. The composition according to claim 3, characterized in that the sodium hypobromite is stabilized with an acid amide derivative selected from the group consisting of: carbonic acids, hydrogen cyanide, carboxylic acids, iono acids, sulfuric acids, phosphoric acids and boric acids s.

6. The composition according to claim 1, characterized in that the industrial fluids are selected from the group consisting of cooling waters; industrial process waters, for food and beverages; pulp and paper mill systems; past eur i zadoras of breweries; freshwater systems; air washing systems; fluids and mud for drilling oil fields; processes for oil recovery; industrial lubricants; heat transfer systems; gas cleaning systems; latex systems; clay and pigment systems; and decoration sources.

7. The composition according to claim 1, characterized in that the amount of stabilized sodium hypobromite ranges from about 0.05 ppm to about 10 ppm, of total residual oxidant, and the amount of the mixture of 5-chloro-2-methyl-4-methyl. -isot iazolin-3-one and 2-met i 1-4-isothiazolin-3-one ranges from about 0.05 ppm to about 6.0 ppm of active ingredients.

8. The composition according to claim 1, for controlling bacteria in recirculating cooling water, characterized in that the weight ratio of the mixtures to the stabilized sodium hypobromite is from about 1.0: 10.0 to about 10.0: 1.0.

9. The composition according to the rei indication 1, for controlling fungi in recirculating cooling waters, characterized in that the weight ratio of the mixtures with respect to the sodium hypobromite is from about 1.0: 10.0 to about 10. 0: 1.0

10. The composition according to claim 1, for controlling algae in recirculating cooling waters, characterized in that the weight ratio of the mixtures with respect to the sodium hypobromite is from about 1.0: 10.0 to about 10.0: 1.0.

11. The composition according to the rei indication 1, for controlling bacteria in paper mill systems, characterized in that the weight ratio of the mixtures with respect to the stabilized sodium hypobromite is from about 1:10 to about 10: 1.

12. A method for controlling microbiological growth, characterized in that it comprises the step of adding to an industrial fluid, containing the growth, a combination of an effective antimicrobial amount, of a mixture of 5-chloro-2-methyl 1-4-isothiazolin -3-one and 2-met i 1-4-i so t iazo lin-3-one, and stabilized sodium hypobromite.

13. The method according to claim 12, characterized in that the microbiological growth is selected from the group consisting of bacteria, fungi, algae and combinations thereof.

14. The method according to claim 12, characterized in that the industrial fluid is selected from the group consisting of: cooling waters; industrial process waters, food and beverages; pulp and paper mill systems; pas t euri zadoras of breweries; freshwater systems; air washing systems; fluids and mud for drilling oil fields; oil recovery processes; industrial lubricants; fluids for cutting; heat transfer systems; gas washing systems; latex systems; clay and pigment systems; and decoration sources.

15. The method according to claim 12, characterized in that the amount of sodium hypobromite stabilized ranges from about 0.05 ppm to about 10 ppm of total residual oxidant, and the amount of the mixture of 5-chloro-2-me thi-4 - 1-tiazolid-3 -one and 2-met i-4-yso t-zolin-3-one vary from about 0.05 ppm to about 6.0 ppm of active ingredients.

16. The method according to claim 12, for controlling the bacteria in cooling waters, characterized in that the weight ratio of the mixtures with respect to the stabilized sodium hypobromite is from about 1.0: 10.0 to about 10.0: 1.0.

17. The method according to claim 12, for controlling fungi in cooling waters, characterized in that the weight ratio of the mixtures with respect to the stabilized sodium hypobromite is from about 1.0: 10.0 to about 10.0: 1.0.

18. The method according to claim 12, for controlling algae in cooling waters, characterized in that the weight ratio of the mixtures to the stabilized sodium hypobromite is from about 1.0: 10.0 to about 10.0: 1.0.

19. The method according to claim 12, for controlling bacteria in pulp and paper mill systems, sarasterized because the weight ratio of the mixtures in relation to the stabilized sodium hypobromite is from about 1.0: 10.0 to about 10.0: 1.0.

20. The method for controlling microbial growth, in accordance with the rei indication 7, characterized in that the pH of the cooling water is controlled within a range of from about 2.5 to about 11.0.

21. The method according to claim 19, characterized in that the pH of the cooling water is controlled within the range from about 6.0 to about 10.

22. A composition for controlling microbiological growth, in industrial fluids, characterized in that it comprises a combination of stabilized sodium hypobromite, with a compound selected from the group consisting of: glutaraldehyde, 2,2-dibromo-3-n or tr ilopropylonamide, 2 - bromine-2-ni tropropan-1,3-diol, 1-bromo-1- (bromomethyl) -1,3-propanedicarbonitrile, t-tetrachloro isof taloni tri lo, alkyldimethylbenzammonium chloride, dimethyldialkyl ammonium chloride, dichloride of poly (oxyethylene (dimethyliminio) ethylene (dimethyl-imino) ethylene, methylene bistiocyanate, 2-deci 1 t io t anamina, t-tetraquishydroxymethyl phosphono phonium, dithiocarbamate, cyanodithioimidocarbonate, 2-methyl-5-nitroimidazole- 1-e tanol, 2- (2-bromo-2-nitroetenyl) furan, be t-bromo-be ta-ni t roe st go o n, be t a-ni t roes pull, beta-ni trovini 1 furan , glut aroni tr i lo of 2-bromo-2-bromomethyl, bi s (trichlororne ti 1) sul phona, S- (2-hydroxypropyl 1) t iome t ansul fonat o, tetr ahidro- 3, 5-dimethyl-2H-l, 3,5-hydrazin-2-thione, 2 - (thiocyanomethylthio) benzothiazole, 2-bromo-4'-hydroxyacetophenone, 1,4-bis (bromoacetoxy) -2-butene, bi s (tributyltylamide), copper sulfate, 2- t -butyl-ylamino) -4-chloro-6- (ethylamino) -s-triazine, dodecylguanidine and hydrochloride dodecylguanidine.

23. A method for controlling microbiological growth, characterized in that it comprises the step of adding, to an industrial fluid containing the growth, a combination of an effective amount of antimicrobial agent, of a compound selected from the group consisting of: glutaraldehyde, 2.2 -dibromo-3-nitri lop ropy onamide, 2 -bromo-2-nor tropropan-1,3-diol, 1-bromo-1- (bromome-1) -1, 3-propanedicarbonitrile, tetrachloro-or-phthalo-tri-lo, alkyldimethyl-ilbenzyl chloride, dimethyl-1-ammonium chloride, poly (oxyethylene (dimethyliminium) ethylene (dimethyl-iminium) et-1-ene dichloride, methylene bisthiocyanate, 2-I- deci 1 t io t anamina, tetraquishidroximetilfosfonio sulfate, dithiocarbamate, cyanodithioimidocarbonate, 2-methyl-5-nitroimide zol-1-ethanol, 2- (2-bromo-2-nitroetenil) furan, be t-bromo-be tañí t roe s tir eno, bet a-ni troes tir eno, beta- ni t rovini 1 fur no, glut aroni tri lo 2-bromo-2-bromomethyl, bis (tr iclorome t il) sul fona, S- (2- hydroxypropyl) thiomethansulfonate, tetrahydro-3, 5-10 dimethyl-2H-1, 3,5-hydrazin-2-thione, 2 - (thiocyanomethylthio) benzothiazole, 2-bromo-4'-hydroxyacetophenone, 1,4-bis ( bromoacetoxy) -2-butene, bi-s (tributyltin) oxide, copper sulfate, 2-1-thbutyl-1-amino) -4-chloro-6- (ethylamino) -15 s-triazine, dodecylguanidine and dodecyl guanidine hydrochloride . twenty 25